Bamboo-based biodegradable mulch film for modern agriculture

Mulch film is a layer of material applied to cover and protect the topsoil. It is highly valued in modern agriculture owing to benefits such as soil moisture retention, soil temperature regulation, beneficial microbial activity, weed growth control, and enhanced crop yields. Unfortunately, the currently popular mulch films based on plastics such as polyethylene are usually non-degradable and cause “white pollution,” affecting both soil quality and crop output. In this regard, biodegradable liquid mulch films based on organic polymers are promising. These films adhere strongly to soil, limit moisture evaporation, do not impede water infiltration, preserve heat, and retain moisture. Furthermore, they improve soil structure, hold the topsoil, and conserve the till layer. However, liquid mulch films typically utilize non-renewable and toxic raw materials such as petroleum asphalt. Consequently, it is necessary to look for sustainable biomass raw materials for mulch film preparation.

With this goal, a group of researchers from China, led by corresponding authors Professors Yiqiang Wu and Zhaoshuang Li from the College of Materials Science and Engineering, Central South University of Forestry & Technology, China, has recently developed an innovative biodegradable liquid slow-release mulch film based on bamboo residue for selenium-enriched crop cultivation. Their findings were published online on 12 May 2025 in Volume 8 of Research, the first journal in the Science Partner Journal (SPJ) program.

Dr. Li explains the motivation behind their research by stating, “Bamboo is an important biomass material with a global cultivation area of over 22 million hectares and abundant production. It is fast-growing, renewable, biodegradable, and environmentally friendly. Furthermore, its residues contain a lot of cellulose. Therefore, there is an urgent need for a breakthrough technology to efficiently utilize bamboo residues.”

The team first prepared sodium carboxymethyl cellulose (CMC) from bamboo residues and leveraged forestry resources to synthesize the compound quaternized lignin (QL) through a quaternization modification process. Later, they combined CMC and QL along with a selenium-containing cross-linking agent in polyvinyl alcohol to obtain a biodegradable liquid mulch film—PVA@CMC/QL—held together by electrostatic interaction. The obtained film was found to possess enhanced spray-film-forming properties as well as the ability to produce a dense mulch film on top of the soil under normal conditions. Furthermore, it exhibited an outstanding oxygen transmission rate and water vapor transmission rate.

Moreover, PVA@CMC/QL has highly desirable moisture retention and insulation properties. Its application increased soil temperature and humidity by 0.4°C–2.1°C and 0.5%–2.8%, respectively, compared to controls. Furthermore, the proposed film exhibited exceptional weed suppression with just 13.3% weed germination under its cover. The film also exhibited UV-blocking properties, further contributing to weed suppression by limiting light penetration.

The researchers showcased the novelty of PVA@CMC/QL through optimal rhizome growth of pak choi seedlings. While roots and stems increased by about 3.8 cm and 1.2 cm, respectively, the selenium content of pak choi seedlings under the mulch was as high as 28.5 μg/kg.
“Our work not only improves the value-added utilization of bamboo residues but also provides new insights into the research on multifunctional bamboo–plastic mulch film. Overall, the development of biodegradable PVA@CMC/QL mulch film is an effective means to address plastic pollution and promote modern green agriculture,” concludes Dr. Wu.

About the Central South University of Forestry and Technology, Hunan, China  

The Central South University of Forestry and Technology (CSUFT) is a multidisciplinary university located in Changsha, Hunan, China. Founded in 1958, the university comprises 24 colleges and departments and offers wide-ranging courses in science, engineering, agriculture, arts, law, economics, management, and education. CSUFT boasts a strength of more than 41,000 students and 2,510 faculty and staff members. It was ranked 201-300 globally for Food Science & Technology and Agricultural Sciences in Academic Ranking of World Universities 2023. The motto of CSUFT is: "Upon nous and truth, we innovate. For nature and nurture, we cultivate."

About Research by Science Partner Journal

Launched in 2018, Research is the first journal in the Science Partner Journal (SPJ) program. Research is published by the American Association for the Advancement of Science (AAAS) in association with Science and Technology Review Publishing House. Research publishes fundamental research in the life and physical sciences as well as important findings or issues in engineering and applied science. The journal publishes original research articles, reviews, perspectives, and editorials. IF=10.7, Citescore=13.3.

Sources: https://doi.org/10.34133/research.0685